There have been various developments in recent years to make all aspects of motor vehicles more efficient. Such increases in efficiency reduce cost and have a positive environmental impact. Large vehicles such as tractor-trailers that are heavily relied on to handle contemporary shipping demands for goods and raw materials are no exception. Indeed, there have been many notable advances with these types of vehicles to make the same more efficient. However, as the cost of fuel continues to rise, there is a continuous effort to offset this increased operating cost and address the environmental impact of combusting excessive fossil fuels by utilizing leaner, lower-cost tractor-trailer type vehicles.
One aspect of the aforementioned tractor-trailer vehicles that has received a significant amount of attention from a cost reduction perspective is the heating, ventilation, and air conditioning (HVAC) system utilized therein. As one example, there has been a growing use of HVAC systems in tractor-trailers that utilize both an engine operated and an electrically operated configuration to provide heating/cooling. Such a system advantageously provides for HVAC service when the engine is running while a driver is operating the vehicle, as well as HVAC service when the engine is not running while a driver is resting in the vehicle. Such a system can be found at U.S. Pat. No. 6,889,762, the entire teachings and disclosure of which is hereby incorporated by reference in its entirety. As another example, there has been a growing desire to make each of the various components within an HVAC loop more efficient, by improving their thermal performance and reducing their power consumption.
While contemporary HVAC systems have vastly improved driver comfort and vehicle flexibility, there is an ongoing need to make such systems more efficient. The embodiments described herein provide various improvements upon the above described HVAC systems. These and other advantages will be apparent from the description provided herein.